Do you ever feel like you are being put on a test to see if you pass or fail it? I can't help but to feel this way at times.
In your case, it probably is a test b/c you said she fears that you would just revert back to your old ways in a year or so. Therefore, you will have to go for a lenght of time in order for her to be convenced that you will remain the improved man.
In rare cases, I think S is good for some M. By that I mean that some couples reach a point that they just get tired of each other. They start to get on each other's nerves and the other one's bad habits are harder to endure. It's like you need a vacation from each other. When the R begins to break down, I wish couples would S before they just jump into D. When I was a kid, that is what people did. D was the very last straw. Of course, you didn't hear of as much back then as you do now. But couples now, sleep together one night and file for D the next day....I just don't get it.
As long as she doesn't file for D then you still have time on your side to show her your changes. Even if she did file for D....if she doesn't remarry, you still have that chance, so don't give up.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!